Date of this Version
HORTSCIENCE 38(2):313–314. 2003
Daleas (prairie-clovers) are annual or perennial, warm season legumes found from southern Canada to South America (Barneby, 1977). They are an important group of legumes in native grasslands of the Great Plains. The genus name Dalea L. is in honor of Samuel Dale, an English botanist (1659–1739). Until recently, these plants were classified in the genus Petalostemon Michx. (Weber, 1990). The prairie-clovers have potential as attractive garden ornamental plants in addition to their importance as constituents of prairies and pastures. They have uses, along with other native species, for beautification of roadsides, rest areas, parks, and recreation areas, and for soil stabilization (Salac et al., 1978). Daleas are common in the Nebraska Sandhills, an area in central Nebraska extending into South Dakota, consisting of almost 50,000 Km2. It is one of the largest grass-stabilized sand dune regions in the world. The Sandhills area has many unique or special plants, such as Penstemon haydenii S. Wats. and Lithospermum caroliniense (Walter) MacMill (Bleed and Flowerday, 1989).
Dalea villosa (Nuttall) Sprengel, commonly known as silky prairie-clover, typically grows in moderately moist to dry sandy soils in disturbed sites, along right-of-ways, and in margins of sandy, wind-eroded blowouts (Farrar, 1990; Great Plains Flora Association, 1986). It has numerous, often horizontal to drooping flowering heads with pinkish-rose colored flowers. Flower spikes are solitary at ends of short branches near the top of the plant (Stubbendieck et al., 1989). Flowers are minute with five protruding yellow stamens encircling a spike up to 10 cm long (Farrar, 1990). Flowers mature acropetally and the fruit is a pod 2.5 to 3 mm long (Barneby, 1977). Plants flower from July to August, depending on location. It has one to several erect, branching stems and a reddish-orange taproot. A compact arching growth habit and an abundance of attractive, silvery, compound leaves give an appearance quite different from other species of the genus (Farrar, 1990). It has numerous alternate, odd-pinnately compound leaves, up to 2 to 4 cm long, with 11 to 25 leaflets, narrowly elliptic and 5 to 11 mm long (Great Plains Flora Association, 1986). Stems and leaves are silvery-green with short, white hairs (Farrar, 1990). Leaves are dotted with glands on the lower surface.
The species is found from Manitoba to central Texas and from western Wisconsin to eastern Colorado (Barneby, 1977).